Ceramic material for high temperature service
Thermal barrier coating made from a thermally sprayable powder that includes yttria stabilized zirconia and hafnia, from 6 to 9 weight percent yttria, and total impurities less than or equal to about 0.1 weight percent. The thermal barrier coating has from about 5 to 250 vertical macro cracks per 25.4 mm length measured along a coating surface and the macro cracks are oriented perpendicular to a surface of a substrate containing said coating.
1. A thermally sprayed barrier coating comprising:
a coating material that includes:
a yttria stabilized material comprising at least one of zirconia and hafnia, wherein the yttria is from 6 to 9 weight percent; and
a purity of said zirconia or said hafnia being at least 99.5 weight percent;
wherein total impurities of said coating material comprises less than or equal to:
about 0.015 weight percent alumina,
about 0.005 weight percent silica,
about 0.002 weight percent titania, and
about 0.002 weight percent magnesia; and
said barrier coating being a collection of frozen droplets or splats formed from the coating material and comprising vertical cracks arranged at repeating intervals and extending in a thickness direction of said thermal barrier coating.
2. The coating of claim 1 , wherein the vertical cracks run from a coating upper surface to a bond coat arranged between a substrate and the thermal barrier coating.
3. The coating of claim 1 , further comprising a bond coating arranged between the substrate and said barrier coating.
4. The coating of claim 3 , wherein the bond coating comprises a MCrAlY bonding layer.
5. The coating of claim 1 , wherein the barrier coating is arranged over a substrate and the substrate a turbine component.
6. The coating of claim 5 , wherein the turbine component is a turbine blade.
7. The coating of claim 1 , wherein the vertical cracks run through an entire thickness of the thermal barrier coating.
8. The coating of claim 1 , wherein the total impurities comprises less than or equal to:
about 0.002 weight percent soda,
about 0.04 weight percent hematite, and
about 0.02 weight percent calcia.
9. The coating of claim 1 , wherein the coating material is formed from a thermally sprayed powder.
10. A method of applying the thermal barrier coating of claim 1 on a substrate, the method comprising:
thermally spraying the coating material of claim 1 onto the substrate so as to form the barrier coating having vertical cracks extending along a direction of a coating thickness.
11. A high purity thermal barrier coating comprising:
a thermally sprayed coating of a high purity zirconia and hafnia coating material, wherein said coating material consists essentially of:
a purity of at least 99.5 weight percent and with less than about 0.015 weight percent alumina impurity;
from 6 to 9 weight percent yttria;
a balance of at least one of zirconia and hafnia stabilized by the yttria;
said thermal barrier coating having a structure formed from a collection of frozen droplets or splats of the coating material and having repeating vertical cracks extending in a thickness direction; and
said vertical cracks extending between an upper surface of said coating and another material layer arranged on a substrate.
12. The coating of claim 11 , wherein the other material layer is a bond coat.
13. The coating of claim 11 , wherein the coating material is a powder and comprises impurities less than or equal to:
about 0.005 weight percent silica,
about 0.002 weight percent titania, and
about 0.002 weight percent magnesia.
14. The coating of claim 11 , wherein the coating material is formed from a thermally sprayed powder.
15. A high purity thermal barrier coating comprising:
a thermally sprayed coating of a high purity yttria stabilized zirconia coating material, wherein said coating material consists essentially of:
from 6 to 9 weight percent yttria;
zirconia stabilized by said yttria;
a purity of at least 99.5 weight percent and with less than about 0.015 weight percent alumina impurity;
said thermal barrier coating being made up of frozen splats of said coating material and having cracks repeating at regular intervals and extending along a thickness direction and between an upper surface of said coating and another material layer arranged on a substrate.
16. The coating of claim 15 , wherein the total impurities comprises less than or equal to:
about 0.005 weight percent silica,
about 0.002 weight percent titania, and
about 0.002 weight percent magnesia.
17. The coating of claim 15 , wherein the coating material is formed from a thermally sprayed powder.
18. A thermal barrier coating comprising:
a coating material that includes between 6.5 and 7 weight percent yttria stabilized zirconia; and
a purity of said coating material being at least 99.5 weight percent;
wherein total impurities of said coating material comprises less than or equal to:
about 0.015 weight percent alumina,
about 0.005 weight percent silica,
about 0.002 weight percent titania, and
about 0.002 weight percent magnesia; and
said thermal barrier coating having a structure made up of splats of said coating material and repeating vertical cracks extending in a thickness direction of said thermal barrier coating.
19. A method of applying the barrier coating of claim 1 , comprising:
spraying a powder material that includes the coating material of claim 1 :
depositing the coating material, formed from the powder material, as a barrier coating on a substrate,
wherein the deposited coating material is a collection of frozen droplets or splats formed from the coating material and comprising vertical cracks arranged a repeating intervals and extending in a thickness direction of said barrier coating.